本文主要針對針縫複合材料進行DCB測試，藉由臨界應變能釋放率 的量測來驗證針縫技術的抗脫層能力及探討不同線材與不同縫線間距對 值的影響，並利用有限元素分析腳架結構是否滿足設計規範。此外，為了達到腳架輕量化的目的，以改變腳架尺寸、疊層層數與纖維轉角的方式對腳架進行最佳化設計，所得的結果可用來提供新腳架設計的參考方針。最後，截取腳架最有可能損傷的區域，建構破壞分析模型以取得其應力場與位移場，並將其代入破壞參數定義式，獲得修正後之破壞參數，以判斷腳架之抗破壞能力。

　　From references, we know that through-thickness stitching can offer a significant improvement in the static delamination resistance of laminated composites. In this article, it is verified by the increasing value of critical strain energy release rate, Gc, determined from the DCB test. By the same test, the effects of different stitch distance and different stitch material on delamination resistance are also observed. After that, a structure analysis of landing bow is executed to see if the bow meets the design standard regulation.
　　In optimum design, the weight of structure is defined as our objective function. Bow size, the number of layers, and lamina orientation are chosen as our design variables. The results of optimum design can be used as reference data for new bow design. Finally, stress fields and displacement fields can be calculated by fracture analysis in the maximum-stress region. Then we can obtain the fracture parameters by substituting stress and displacement fields into the modified definition of fracture parameters. The calculated fracture parameters can be utilized to judge the delamination resistance of the landing bow.

[1]Huang, S.L., Richey, R.J., Deska, E.W., “Cross Reinforcement in a GR/EP laminate,” American Society of Mechanical Engineers, Winter Annual Meeting , San Francisco,10-15 December 1978
[2]Mignery, L.A., Tan, T.M., Sun, C.T., “The Use of Stitching to Suppress Delaminations in Laminated Composites,” American Society for Testing and Materials, pp371-385. ,1985
[3]Dransfied, K., Baillie, C., Mai, Y.W., “Improving the Delamination Resistance of CERP by Stitching,” Composites Science and Technology, Vol.50,pp305-317.,1994
[4]Mouritz, A.P., Leong, K.H., Herszberg, I., “A Review of the Effect of Stitching on the In-Plane Mechanical Properties of Fiber Reinfoced Polymer Composites,” Composites Part A, Vol.28,pp979-991.,1997
[5]Mouritz, A.P., Bannister, M.K., Falzon, P.J., Leong, K.H., “Review of Applications for Anvanced Three-Dimensional Fiber Textile Composites,” Composite Part A, Vol.30,pp1445-1461 ,1999
[6]Mouritz, A.P., Cox, B.N., “A Mechanistic Approach to the Properties of Stitched Laminates,” Composites A, Vol.31,pp1-27.,2000
[7]Dransfield, K.A., Jain, L.K., Mai, Y.W., “On the Effects of Stitching in CFRPs-I. Mode I Delamination toughness,” Composites Science and Technology, Vol.58,pp815-827.,1998
[8]Jain, L.K., Dransfield, K.A., Mai, Y.W., “On the Effects of Stitching in CFRPs-II.Mode II Delamination toughness,” Composites Science and Technology, Vol.58,pp829-837.,1998
[9]Jain, L.K., Dransfield, K.A., Mai, Y.W., “Effect of Reinfocing Tabs on the Mode I Delanination Toughness of stitched CFRPs,” Journal of Composite Materials, Vol.32,pp2046-2041.,1998
[10]He, M., Cox, B.N., “Crack Bridging by Through-Thickness Reinfocement in Delaminating Curved Structures,” Composites Part A, Vol.29,pp377-393.,1998
[11]Cox, B.N., “A Constitutive Model for Through-Thickness Reinforcement Bridging Delamination Crack,” Advanced Composite Letters, Vol.8,pp249-256.,1999
[12]Rugg, K.L., Cox, B.N., Massabo R“Mixed Mode Delamination of Polymer Composite Laminates Reinforced through the Thickness by z-fibers,” Composites Part A, Vol.33,pp177-190.,2002
[13]ANSYS 7.0 Documentation : ANSYS,Inc. Theory Reference.
[14]Denn, M. M , “Optimization by Variational Methods, ” McGraw-Hill, New York ,1969
[15]Williams, M.L., “The Stress Around a Fault or Crack in Dissimilar Media,”Bulletin of the Seismological Society of America, Vol.49,pp199-204.,1959
[16]Rice, J.R., “Elastic Fracture Mechanics Concepts for Interfacial Cracks,” J. of Applied Mechanics, Vol. 55, pp.98-103. ,1988
[17]Wu, K.C., “Stress Intensity Factors and Energy Release Rate for Interfacial Cracks Between Dissimilar Anisotropic Materials,” J. of Applied Mechanics, Vol. 57, pp.882-886. ,1990
[18]Hwu, C., “Fracture Parameters for Orthotropic Bimaterial Interface Cracks,” Engineering Fracture Mechanics, Vol.45, No.1, pp.89-97. ,1993b
[19]Sun, C.T. and Jih, C.J., “On Strain Energy Release Rates for Interfacial Cracks in Bimaterial Media,” Engineering Fracture Mechanics, Vol. 28, No. 1, pp.13-20. ,1987
[20]Sun, C.T. and M. G. Manoharan, “Strain Energy Release Rates of an Interfacial Cracks between Two Orthotropic Solids,” J. Composite Materials, Vol. 23,pp.460-478. ,1989
[21]M. G. Manoharan and Sun, C.T., “Strain Energy Release Rates of an Interfacial Cracks between Two Anisotropic Solids under Uniform Axial Strain,” J. Composite Materials, Vol. 23,pp.460-478. ,1989
[22]Hwu, C., Kao, C. J. and Chang, L. E., “Delamination Fracture Criteria for composite Laminates,”J. Composite Materials, Vol. 29, No.15, pp.1962-1987. , 1995
[23]Bascom, W.D., Bitner, R.J., Moulton, R.J.,and Siebert, A.R., “The Interlaminar Fracture of Organic-Matrix Woven Reinfoced Composites,” Composites, Vol. 11, pp.9. , 1980
[24]Wilkins, D.J., Eisenmann, J.R., Camin, R.A., Margolis, W.S., and Benson, R.A., “Characterizing Delamination Growth in Graphite-Epoxy,”Damage in Composite Materials, ASTM STP 775, pp.168. , 1980
[25]楊文彬、胡潛濱、林晃業、陳俊佑, “496直昇機腳架之材料試片製作及Gc值之量測”, 成功大學航空太空研究所,民國92年 8月
[26]張惟碩, “496直昇機腳架結構設計報告”, 中科院第一研究所航空結構組,民國89年 8月
[27]ANSYS 7.0 Documentation : ANSYS Element Reference.
[28]柯著成, “496直昇機腳架結構分析報告”, 中科院第一研究所航空結構組,民國89年 8月
[29]Ting, T.C.T., Anisotropic Elasticity:Theory and Applications. Oxford University Press, 1996
[30]ANSYS 7.0 Documentation : Structurcal Analysis Guide.